Lourn

In 2372, Worf often conversed with Lourn on their people when Worf was on leave after the destruction of the USS Enterprise. Lourn believed that their race would soon cause a conflict with another empire if none came to them. Lourn also chastened Worf for denying his Klingon nature by serving in Starfleet. After being cast out of Klingon society for opposing the invasion of the Cardassian Union, Worf went to see Lourn to tell him the teachings of Boreth were corrupting the Klingon race and could lead to its destruction. (DS9novelization: The Way of the Warrior)